The invention is related to the field of data storage and, in particular, to a rotating tape cartridge picker that exchanges tape cartridges between at least one tape cartridge storage location and at least one tape drive in a tape cartridge autoloader/library system.
A popular device for handling large amounts of information in a data processing system is an automated tape cartridge library. Tape cartridge libraries store and manage multiple tape cartridges containing magnetic tape media on which data is stored. Tape cartridge libraries include a plurality of fixed tape cartridge storage locations, at least one read/write tape drive, and a tape cartridge retrieval/transport mechanism, known in the art as a xe2x80x9ccartridge picker.xe2x80x9d The tape cartridge storage locations are arranged in predetermined arrays of uniquely identified cells with each cell containing a single tape cartridge. Each of the individual tape cartridges includes a computer readable identifying indicia, such as a bar code, used to identify the tape cartridge for retrieval by the cartridge picker.
Cartridge pickers automatically exchange individual tape cartridges between their storage locations and the tape drive(s). Different types of cartridge pickers are used to accommodate the various tape cartridge arrangements in different tape cartridge libraries. One example of a cartridge picker utilizes a rotatable robotic arm with an optical sensor for selecting and retrieving the correct tape cartridge and transporting the tape cartridge to the tape drive(s). Another example of a cartridge picker utilizes a linear robotic mechanism that moves along an X-Y translation or about a pivot in a rotary motion to select, retrieve, and transport tape cartridges to the tape drive(s). The tape drive(s) is operable to read/write data from or to the magnetic tape in the tape cartridge.
A host computer communicates with a library control unit and the tape drive(s) to control the operation of the tape cartridge library.
Unfortunately, tape cartridge pickers are complex mechanisms that must translate among the multiple fixed tape cartridge storage locations, moving in two or three dimensions to retrieve desired tape cartridges for delivery to the tape drive(s). Thus, the tape cartridge picker is a considerable factor in the overall size of a tape cartridge library. For example, in a typical retrieval process from a storage location, the tape cartridge picker must move, usually along an X-axis, to a tape cartridge storage location, orient with the storage location, retrieve a tape cartridge from the location, move again along the X-axis to the tape drive location, orient with the tape drive, and load the tape cartridge.
Additionally, the complexity of tape cartridge pickers account for a significant component of the cost of tape cartridge libraries and require a significant amount of space to implement. In many applications, the cost of a tape cartridge library cannot be justified unless there are a large number of tape cartridges that are stored and managed by the tape cartridge library.
The present invention solves the problems outlined above and advances the art by providing a rotating tape cartridge picker for a tape cartridge library, termed xe2x80x9cautoloader/library systemxe2x80x9d herein. The present tape cartridge picker includes a turntable that rotates in a fixed base to interface with at least one tape cartridge storage location and at least one tape drive. The turntable includes a cavity configured to receive an individual tape cartridge. The cavity is defined in the turntable about a central axis of rotation so that once received in the cavity, the tape cartridge may be rotated within the turntable for delivery to at least one storage location or at least one tape drive. Advantageously, the present cartridge picker does not translate in two or three dimensions as in the prior art, but instead merely rotates within the base to position the tape cartridge picker to exchange tape cartridges with at least one storage location and at least one tape drive.
The tape cartridges are loaded onto the turntable using a translation arm that extends horizontally from the turntable to engage or hook a tape cartridge and pull the tape cartridge into the cavity. The tape cartridges are unloaded from the turntable by extending the translation arm to slide the tape cartridge out of the cavity and into at least one storage location or the at least one tape drive.
A first advantage of the present tape cartridge picker is the limited motion required to exchange tape cartridges between the various components of the autoloader/library system. For example, in prior art systems, the robotic cartridge picker must move to the storage location of a desired tape cartridge, select the tape cartridge from the storage location, move to the location of the tape drive and load the tape cartridge into the tape drive. As one skilled in the art will greatly appreciate, these operations are time consuming and require the use of complex mechanisms to move the picker within the autoloader/library system. In contrast, the present cartridge picker simply rotates between the storage locations and tape drive(s) to retrieve and deliver tape cartridges. Advantageously, this provides a fast and efficient exchange of tape cartridges within an autoloader/library system. A second advantage of the present tape cartridge picker is that it permits autoloader/library systems to be architected with coplanar components to is achieve a substantially smaller form factor. A third advantage of the present cartridge picker is that the simple construction and mechanisms used to implement the picker result in a significantly reduced cost in producing autoloader/library systems. A fourth advantage of the present tape cartridge picker is that, in the case of an autoloader/library system that is configured to mechanically and electrically interconnect with other substantially identical autoloader/library systems in a stacked configuration, the picker can be elevated to access multiple autoloader/library systems. Advantageously, elevating the cartridge picker in stacked autoloader/library systems permits tape cartridge sharing and provides efficient load balancing. A fifth advantage of the present cartridge picker is that its operation is independent of the other components of an autoloader/library system. The tape drive(s) can be reading and writing data, while the cartridge picker shuttles tape cartridges between various storage locations and other tape drives in the autoloader/library system.